Benchmark: spread operator vs reusing object

Tests:

spread operator
const query = { 'ssoToken': '123', 'customerNum': '456' }; const proxyQueryParams = ['ssoToken', 'customerNum']; proxyQueryParams .filter(paramKey => query[paramKey] !== undefined) .reduce((params, paramKey) => ({ ...params, [paramKey]: query[paramKey], }), {});
reuse object
const query = { 'ssoToken': '123', 'customerNum': '456' }; const proxyQueryParams = ['ssoToken', 'customerNum']; proxyQueryParams .filter(paramKey => query[paramKey] !== undefined) .reduce((params, paramKey) => ({ ...params, [paramKey]: query[paramKey], }), {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread operator
reuse object

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36

Browser/OS: Chrome 67 on Mac OS X 10.12.6

View result in a separate tab

Test name	Executions per second
spread operator	750793.6 Ops/sec
reuse object	783396.8 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):

LLMs can make mistakes. Check important info.

I'll break down the benchmark and its results to explain what's being tested, compared, and analyzed.

**What is being tested?**

The benchmark compares two approaches to filter and reduce an object:

1. **Spread operator approach**: This method uses the spread operator (`...`) to create a new object by copying properties from another object. The `reduce` method is then used to iterate over the filtered array of property keys, creating a new object with the corresponding values.
2. **Reuse object approach**: This method reuses an existing object (`params`) and iteratively adds new key-value pairs to it using the `reduce` method.

**What options are compared?**

The two approaches being compared differ in how they create a new object:

1. Spread operator: Creates a new object by copying properties from another object.
2. Reuse object: Uses an existing object (`params`) and iteratively adds new key-value pairs to it.

**Pros and Cons of each approach:**

1. **Spread operator approach**:
	* Pros:
		+ Creates a new object with a clear and concise syntax.
		+ Avoids mutating the original object, which can be beneficial for code readability and maintainability.
	* Cons:
		+ May incur additional overhead due to creating a new object.
2. **Reuse object approach**:
	* Pros:
		+ Can be more efficient in terms of memory allocation, as it reuses an existing object.
	* Cons:
		+ Requires careful handling to avoid mutating the original object unintentionally.

**Libraries and features:**

There are no external libraries mentioned in the benchmark definition. However, the `reduce` method is a built-in JavaScript method that is not specific to any library.

**Special JS feature or syntax:**

The benchmark uses the spread operator (`...`) and template literals (e.g., `"paramKey": query[paramKey]`). These features are part of the ECMAScript standard and have been supported in modern browsers for a while. However, if you're targeting older browsers, you might need to use polyfills or fallback solutions.

**Other alternatives:**

If you wanted to test an alternative approach, here are a few options:

1. **Using `Object.assign()`**: Instead of the spread operator, you could use `Object.assign()` to create a new object.
2. **Using `Array.prototype.map()` and `Array.prototype.reduce()`**: You could convert the filtered array of property keys to an array and then use `map` and `reduce` to create a new object.
3. **Using a loop with object literal syntax**: You could use a traditional loop with object literal syntax (`obj[key] = value;`) instead of the spread operator or reuse object approach.

Keep in mind that these alternatives might not be as concise or readable as the original approaches, and some might have performance implications depending on the specific use case.

Related benchmarks:

spread operator vs reusing object (version: 0)

Comparing performance of: spread operator vs reuse object

Created: 6 years ago by: Guest

Jump to the latest result

spread operator

reuse object

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):